GB2427480A - Electrochemcial gas sensor with integral test gas generator connected via a conduit - Google Patents
Electrochemcial gas sensor with integral test gas generator connected via a conduit Download PDFInfo
- Publication number
- GB2427480A GB2427480A GB0611897A GB0611897A GB2427480A GB 2427480 A GB2427480 A GB 2427480A GB 0611897 A GB0611897 A GB 0611897A GB 0611897 A GB0611897 A GB 0611897A GB 2427480 A GB2427480 A GB 2427480A
- Authority
- GB
- United Kingdom
- Prior art keywords
- gas
- gas sensor
- generator
- conduit
- measuring electrode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000009792 diffusion process Methods 0.000 claims description 8
- 239000012528 membrane Substances 0.000 claims description 4
- 238000000034 method Methods 0.000 claims description 3
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 3
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 2
- 229920000642 polymer Polymers 0.000 claims 1
- 238000005259 measurement Methods 0.000 abstract description 6
- 239000007789 gas Substances 0.000 description 85
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 4
- -1 polypropylene Polymers 0.000 description 3
- 229910021529 ammonia Inorganic materials 0.000 description 2
- ZCCIPPOKBCJFDN-UHFFFAOYSA-N calcium nitrate Chemical compound [Ca+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ZCCIPPOKBCJFDN-UHFFFAOYSA-N 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 150000003863 ammonium salts Chemical class 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005868 electrolysis reaction Methods 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 229910052741 iridium Inorganic materials 0.000 description 1
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 239000012266 salt solution Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
- G01N27/403—Cells and electrode assemblies
- G01N27/404—Cells with anode, cathode and cell electrolyte on the same side of a permeable membrane which separates them from the sample fluid, e.g. Clark-type oxygen sensors
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
- G01N27/416—Systems
- G01N27/4163—Systems checking the operation of, or calibrating, the measuring apparatus
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
- G01N27/416—Systems
- G01N27/417—Systems using cells, i.e. more than one cell and probes with solid electrolytes
- G01N27/4175—Calibrating or checking the analyser
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/0004—Gaseous mixtures, e.g. polluted air
- G01N33/0006—Calibrating gas analysers
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/0004—Gaseous mixtures, e.g. polluted air
- G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
- G01N33/007—Arrangements to check the analyser
Abstract
A compact gas sensor arrangement, to which a test gas can be admitted without the use of mechanical components and whose readiness for measurements during the calibration is interrupted only for a short period, consists of the combination of an electrochemical gas sensor (3) and an electrochemical gas generator (2) with a gas conduit (1) from the gas generator (2) to the measuring electrode (9) of the gas sensor (3), whereby the measuring gas from the surroundings of the gas sensor (3) has free access to the measuring electrode (9).
Description
2427480
Gas sensor arrangement with electrochemical gas generator The invention relates to a gas sensor arrangement.
For the purpose of functional control or calibration, a given test gas or ambient gas (ie gas in the surroundings of the sensor to be measured by the gas sensor) has to be admitted to electrochemical gas sensors at regular intervals. This generally takes place manually using compressed gas containers or with calibration gas containers or under normal pressure, or automatically using chemical or electrochemical gas generators, such as described for example in GB 2 254 696 A. Common to these methods is the fact that the electrochemical gas sensor is not available for measurements or ambient gas during the calibration.
The present invention is as claimed in the claims.
The present invention makes available a compact gas sensor arrangement with an electrochemical gas sensor, to which a test gas can be admitted for calibration or test purposes without the use of mechanical components such as valves, whereby not only the electrochemical system, but also the gas path to the gas sensor can be checked and the readiness for measurements is not interrupted or interrupted for a short period, only.
The measuring electrode of the gas sensor and the working electrode of the gas generator are preferably arranged in a plane, and the generated test gas conveyed via a gas conduit to the electrochemical gas sensor. The gas conduit may project into a region of the measuring electrode that is freely accessible by the diffusion of measuring gas from the surroundings of the gas sensor and be formed in such a way that as small an area as possible of the measuring electrode is covered and the gas sensor can be exposed frontally to test gas. By switching on the gas generator via a control and analysis unit, the gas sensor can be tested and it is then immediately ready for measurements of ambient gas. By employing a plausibility approach, the gas sensor can also remain in the
-2-
measuring mode during calibration. Both the calibration gas generation and the gas sensor signal are connected via the common control and analysis unit. The quantity of generated test gas is proportional to the current through the gas generator, so that the gas sensor also displays a proportional sensor current. If a supply of ambient gas also takes place from the surroundings, the sensor current will be higher by a corresponding amount, so that the actual ambient gas concentration in the surroundings can be deduced from a knowledge of the generator current.
An example of embodiment of the invention is explained below with the aid of the figures of which:
Figure 1 is a schematic cross-sectional diagram of a gas sensor arrangement; and
Figure 2 is a schematic plan view of the arrangement according to figure 1.
A gas generator 2 and an electrochemical gas sensor 3 are connected to one another on the gas side via gas conduit 1, in such a way that test gas or calibration gas generated in gas generator 2 can pass without gas loss into a region of measuring electrode 9 of gas sensor 3 that is freely accessible by diffusion. The test gas or calibration gas is generated at a working electrode 4 of gas generator 2 and diffuses through a porous or inherently permeable membrane 7 and interior space 5 of gas conduit 1 to a porous or inherently permeable diffusion membrane 8 and is detected at measuring electrode 9 of gas sensor 3.
An opening 6 of gas conduit 1 projects into a region 10 of measuring electrode 9 of the gas sensor that is freely accessible by diffusion of ambient gas from the surroundings of gas sensor 3 and which is preferably opened in the direction thereof and arranged centrally. Gas conduit 1 is formed in such a way that as little as possible of accessible region 10 is covered.
-3 -
Opening 6 of gas conduit 1 is preferably provided within or at most at the level of housing edge 11, in order to minimise gas losses into the surroundings and flow effects. Housing edge 11 can be raised artificially, but that leads to a restriction of the spherical diffusion and thus to a reduction of the measurement signal. An arrangement that is too close with a spacing of opening 6 of less than 0.5 millimetres influences the free diffusion of the measuring gas to gas sensor 3, or more precisely to measuring electrode 9, and should therefore be avoided.
Gas generator 2 and gas sensor 3 are accommodated in a space-saving manner in a housing 16 made of a plastics material such as for example polypropylene, polyethylene or polytetrafluorethylene, in order to keep gas conduit 1 as short as possible. Reference electrodes 12, 14 and counter-electrodes 13, 15 of the electrochemical systems are shown in the drawing for the sake of completeness. The generation of calibration gas and the gas sensor signal are operated via a common control and analysis unit 20, which is connected by means of connection lines 17, 18, 19 and 21, 22, 23 to the electrodes of both electrochemical systems.
The combination of gas sensor 3, gas generator 2 and gas conduit 1 can also be constructed in a modular fashion and can be connected so as to be mechanically detachable. In particular, gas conduit 1 can be designed as an independent connection part, which is fitted on when it is not an integral component of housing 16. Preferred materials for gas conduit 1 are chemically resistant plastics with a smooth surface, in order to avoid adsorptions in interior space 5.
The length of gas conduit 1 should, ideally, not exceed 30 millimetres and the cross-sectional area through which a flow can freely pass should lie between 0.2 and 5 square millimetres.
The electrodes of gas sensor 3 are preferably platinum/PTFE composite electrodes.
-4-
The gas generation in gas generator 2 takes place by switching on an electric voltage between working electrode and counter-electrode 4, 15 of gas generator 2. Hydrogen and oxygen, for example, arise through electrolysis of water. The hydrogen diffuses via gas conduit 1 to gas sensor 3 and is detected there. Alternatively, a gas sensor 3 for the measurement of ammonia comprises for example three iridium electrodes with a suitable electrolyte such as for example a calcium nitrate solution.
The gas generation in gas generator 2 takes place in this case by the application of an electric voltage at working electrode and counter-electrode 4, 15, measured against reference electrode 14 in an ammonium salt solution. The shift in the pH value leads to a liberation of ammonia, and this diffuses via gas conduit 1 to gas sensor 3.
-5-
Claims (11)
1. A gas sensor arrangement including an electrochemical gas sensor, an electrochemical gas generator and a gas conduit extending from the gas generator to the vicinity of the measuring electrode of the gas sensor, and in which ambient gas from the surroundings of the gas sensor has free access to the measuring electrode.
2. The gas sensor according to claim 1, in which the measuring electrode is covered with a porous or inherently permeable diffusion membrane.
3. The gas sensor according to claim 1 or 2, in which the electrodes of the gas sensor and the gas generator are connected to a control and analysis unit.
4. The gas sensor according to any one of the preceding claims, in which the combination of gas sensor, gas generator and gas conduit are mechanically detachable from each other.
5. The gas sensor according to any one of the preceding claims, in which the gas sensor and the gas generator are arranged beside one another in a planar fashion.
6. The gas sensor according to any one of the preceding claims, in which the gas sensor and the gas generator have a circular cross-section.
7. The gas sensor according to any one of the preceding claims, in which the gas conduit has a length of at most 30 millimetres and a cross-sectional area of 0.2 to 5 square millimetres.
8. The gas sensor according to any one of preceding claims 2 to 7, in which the diffusion membrane (8) is made of a polymer, in particular of PTFE.
-6-
9. A method of operating a gas sensor arrangement comprising leading a test gas from an integral electrochemical gas generator to the vicinity of a measuring electrode of the gas sensor in a manner which also allows free access of ambient gas to the measuring electrode.
10. A gas sensor substantially as hereinbefore described with a reference to, and/or as shown in, the accompanying drawings.
11. A method of operating a gas sensor substantially as hereinbefore described.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102005028246A DE102005028246B4 (en) | 2005-06-17 | 2005-06-17 | Gas sensor arrangement with electrochemical gas generator |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB0611897D0 GB0611897D0 (en) | 2006-07-26 |
| GB2427480A true GB2427480A (en) | 2006-12-27 |
| GB2427480B GB2427480B (en) | 2010-05-26 |
Family
ID=36775722
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0611897A Active GB2427480B (en) | 2005-06-17 | 2006-06-15 | Gas sensor arrangement with electrochemical gas generator |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US7704356B2 (en) |
| DE (1) | DE102005028246B4 (en) |
| GB (1) | GB2427480B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2172531A1 (en) | 2008-10-03 | 2010-04-07 | Siemens Aktiengesellschaft | Function test for a gas alarm system |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102006038364B3 (en) * | 2006-08-16 | 2007-08-30 | Dräger Safety AG & Co. KGaA | Electro-chemical gas generator for producing carbon monoxide as testing or calibration gas, has cathode and anode staying in direct contact with electrolytes, and control unit serving as power source and connected with anode and cathode |
| DE102006046464A1 (en) | 2006-09-29 | 2008-04-10 | Dräger Safety AG & Co. KGaA | Electrochemical gas generator for flammable gases |
| DE102009036012A1 (en) | 2009-08-04 | 2011-02-17 | Knick Elektronische Messgeräte GmbH & Co. KG | Electrochemical sensor for measuring the oxygen partial pressure in a process fluid and method for its functional test |
| DE102009052957A1 (en) * | 2009-11-12 | 2011-06-09 | Dräger Safety AG & Co. KGaA | Gas sensor with test gas generator |
| WO2012082113A1 (en) * | 2010-12-14 | 2012-06-21 | Utc Fire & Security Corporation | Thin film micromachined gas sensor |
| US9110041B2 (en) * | 2011-08-04 | 2015-08-18 | Aramco Services Company | Self-testing combustible gas and hydrogen sulfide detection apparatus |
| WO2013189175A1 (en) | 2012-06-21 | 2013-12-27 | 无锡市尚沃医疗电子股份有限公司 | Method and device for measuring concentration of substance in fluid |
| JP6372017B2 (en) * | 2013-07-22 | 2018-08-15 | 新コスモス電機株式会社 | Detector |
| DE102014108109A1 (en) * | 2014-06-10 | 2015-12-17 | Endress + Hauser Conducta Gesellschaft für Mess- und Regeltechnik mbH + Co. KG | Method for calibrating a gas sensor and mobile calibration unit for a gas sensor positioned in a process control system |
| DE102015012440B4 (en) | 2015-09-28 | 2020-02-13 | Dräger Safety AG & Co. KGaA | Electrochemical gas generator for ammonia using ionic liquids and using the gas generator |
| EP3173784B1 (en) * | 2015-11-24 | 2020-11-18 | LAMTEC Meß- und Regeltechnik für Feuerungen GmbH | Gas measuring arrangement with test gas generation unit |
| DE102016003284B4 (en) * | 2016-03-18 | 2022-05-19 | Dräger Safety AG & Co. KGaA | Gas measuring device with a test device for checking a gas sensor |
| US10900942B2 (en) * | 2018-10-15 | 2021-01-26 | Honeywell International Inc. | Device and method for detecting restrictions in gas access to a gas sensor |
| CN111537670B (en) * | 2020-04-20 | 2022-06-10 | 中国科学院上海微系统与信息技术研究所 | Top contact type gas testing cavity and dynamic gas testing system applying same |
| DE102020132771A1 (en) | 2020-12-09 | 2022-06-09 | Dräger Safety AG & Co. KGaA | gas meter |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4444645A (en) * | 1981-07-28 | 1984-04-24 | Bayer Aktiengesellschaft | Measuring apparatus for the analytical determination of a gas partial pressure |
| GB2362959A (en) * | 1999-04-01 | 2001-12-05 | Central Research Lab Ltd | A gas sensor |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2254696A (en) | 1991-04-09 | 1992-10-14 | Emi Plc Thorn | Gas sensor and calibration device |
| GB9510454D0 (en) * | 1995-05-24 | 1995-07-19 | City Tech | Electrochemical gas sensor assembly |
| GB9625463D0 (en) * | 1996-12-07 | 1997-01-22 | Central Research Lab Ltd | Gas sensors |
| CA2309646C (en) * | 1997-11-10 | 2004-04-20 | Central Research Laboratories Limited | A gas sensor |
| US6200443B1 (en) * | 1998-09-29 | 2001-03-13 | Atwood Industries, Inc. | Gas sensor with a diagnostic device |
| US6948352B2 (en) * | 2002-02-07 | 2005-09-27 | Walter Kidde Portable Equipment, Inc. | Self-calibrating carbon monoxide detector and method |
| GB2407870B (en) * | 2003-11-10 | 2006-09-06 | Kidde Ip Holdings Ltd | Self-testing gas detector |
-
2005
- 2005-06-17 DE DE102005028246A patent/DE102005028246B4/en active Active
-
2006
- 2006-04-24 US US11/379,880 patent/US7704356B2/en active Active
- 2006-06-15 GB GB0611897A patent/GB2427480B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4444645A (en) * | 1981-07-28 | 1984-04-24 | Bayer Aktiengesellschaft | Measuring apparatus for the analytical determination of a gas partial pressure |
| GB2362959A (en) * | 1999-04-01 | 2001-12-05 | Central Research Lab Ltd | A gas sensor |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2172531A1 (en) | 2008-10-03 | 2010-04-07 | Siemens Aktiengesellschaft | Function test for a gas alarm system |
| US8159359B2 (en) | 2008-10-03 | 2012-04-17 | Siemens Aktiengesellschaft | Function check for a gas-alarm annunciator |
Also Published As
| Publication number | Publication date |
|---|---|
| US7704356B2 (en) | 2010-04-27 |
| GB2427480B (en) | 2010-05-26 |
| US20060283707A1 (en) | 2006-12-21 |
| GB0611897D0 (en) | 2006-07-26 |
| DE102005028246B4 (en) | 2007-05-03 |
| DE102005028246A1 (en) | 2006-12-28 |
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